Most printing systems in use today utilize printing plates or cylinders which are engraved or photochemically processed to create an image thereon. Ink is then deposited on the plate or cylinder and the ink is thereafter transferred to a substrate, such as paper. In a conventional printing press, a number of pages are printed on a sheet of paper to form a signature which is then folded and assembled with other signatures. The assembled signatures are then bound, trimmed and finished by finishing apparatus to produce finished books, such as magazines, catalogs or any other printed and bound matter.
Often, there is a need to produce different versions of books and/or customized books within a single press run. For example, it may be desirable to produce a number of standard books together with a number of books having additional and/or different signatures or pages therein. Also, it may be necessary or desirable to provide customized information in the form of an address label, personalized information or the like on the inside or outside of finished books. In either case, conventional printing systems are not easily adaptable to produce books of these types.
A printing system which has the ability to produce differing book versions and/or books with customized information is disclosed in Riley U.S. Pat. No. 4,121,818, assigned to the assignee of the instant application. The printing system includes a number of packer boxes disposed adjacent a binding chain wherein each packer box stores a plurality of signatures. A control is included for controlling the packer boxes to selectively feed signatures onto chain spaces of the binding chain so that books of varying content can be produced. Customized information can be printed on the signatures by means of an ink jet printer which is selectively operated by the control. Other types of customization can be effectuated, such as by inserting or onserting cards or the like.
Other systems for producing customized books are disclosed in Abrams et al. U.S. Pat. No. 3,899,165, Wong et al. U.S. Pat. Nos. 4,500,083 and 4,674,052, Wong U.S. Pat. No. Re 32,690 and Berger et al. U.S. Pat. Nos. 4,768,766 and 4,789,147.
Image manipulating systems have been developed which permit gathering of images in an office or home environment. For example, conventional word processing programs, such as MICROSOFT WORD.RTM., WORDPERFECT.RTM. and the like, permit a user to import images into a page and also allow a user to command which pages of a document to print. In addition, macros (i.e., a sequence of commands) can be assembled and executed within these programs which can allow printing of particular document pages in a certain order. Still further, most word processing programs have merge capability wherein a customized image is merged with other standardized information and printed or displayed. As one example, customized information in the form of addressee and address information may be merged with standardized return address information and printed on a series of envelopes.
A different image gathering capability provided by CAD (computer aided design) software, sometimes referred to as "layering," involves the creation and storage of a base page and one or more layer pages. A user can issue commands to display or print the base page and one or more of the layer pages simultaneously atop one another to achieve an effect similar to the overlay of transparencies so that a composite page appearance results.
While the foregoing image manipulating systems allow some image gathering capability, none is effective to assist in the rapid production of different book versions. Of course, CAD systems are primarily designed for line art and not text nor graphic images, and hence are of only limited use. Further, if one were to use word processing software to produce book versions it would be necessary to issue commands to separately print the pages of each book version just before such version is to be produced. That is, a user would have to create and store pages to be included in a first book version and then command the software to print as many copies of the first version as are needed. Thereafter, the user would have to recall the pages of the first version from memory, edit and store the pages to create pages to be included in a second book version and then command the system to print the required number of books of the second version. Similar steps would have to be undertaken for each other book version to be produced. Alternatively, the pages of the different book versions could be created and stored and thereafter printed together. In either event, where many book versions are to be produced, such a process would be quite time-consuming. In addition, image importation and merge routines provided as a part of word processing software are adapted for use on a sub-page basis only and hence are of only limited usefulness in the book production environment. Still further, data manipulated by word processing software are largely (if not entirely) in symbolic format. As a result, data to be displayed or printed must be first rasterized by a raster image processor (RIP), which utilizes complex and time-consuming computational routines which further increase production time to an economically impractical level.
Recently, new printing systems have been developed, called "demand printers," which are capable of high speed printing of images from electronic representations thereof. The demand printer produces high quality color images using a set of fusible toners in an electrophotographic process. More particularly, a web of paper is passed adjacent a series of drums, each of which has been electrostatically charged according to an image pattern for a particular color to be applied to the web. The charge is transferred to the paper and an oppositely charged toner of the proper color is brought into contact with the paper. The oppositely charged web and toner attract so that the toner is held on the paper as other colors are applied thereto. The toners and paper are thereafter heated to fuse the toners to the paper to produce the final image. The web is then cut into sheets (or "forms") and the forms are further processed as needed to produce a final product.
Unlike conventional presses which utilize engraved or photochemically prepared plates or cylinders, demand printers are capable of rapidly printing high quality images of differing content owing to the fact that the images are produced by an electrophotographic process. That is, instead of the need to replate and re-engrave a gravure cylinder when a different image is to be printed therewith, it is only necessary to change the charge applied to the drums of the printer in order to make such change. Thus, different images can be printed by the same printer without significant delays. This advantage makes the demand printer desirable for use in certain production environments. However, applicants are currently unaware of any systems developed by others which utilize this advantage to produce differing book versions in an efficient manner.
Properly controlled demand printing presses offer significant advantages over the prior art. Nonetheless, they are not infallible. Although error rates for such presses are low, from time to time an error such as a missed book or a missed sheet from a book can occur. In some demand printers (termed herein "one book per job printers"), the printing of each book is processed as a complete job or production run. In such printers, only one book is printed at a time. In other words, the demand printer will not start printing a new book until the current book is satisfactorily printed thereby creating a natural pause in the printing process. This natural pause renders "reordering" a book when an error is detected relatively straightforward. Specifically, the demand printer simply reruns the current job.
In other demand printers (termed herein "multiple books per job printers"), a job or production run is processed as a stream of books to be printed. Such streams are often on the order of 1,000 books or more. Once a job is started on such a printer, the stream of books is continually printed from the first book to the last. In other words, the press does not necessarily wait for the complete printing of a first book before beginning to print a second book. In the past, when errors occurred on this latter-type of demand printing press, the press operator was often forced to identify errored books and to manually request the press to reprint the errored books after the corresponding job of printing 1,000 or more books was completed.
As is well known, the United States Post Office offers various levels of discounts for pre-sorted mass-mailings meeting various sorting definitions. For example, a first discount level such as an automated carrier route discount is provided for mailings of ten pieces of mail or more sorted by carrier route; a second discount level such as an automated five digit discount is provided for mailings of ten pieces or more sorted by five-digit zip codes; a third discount level such as an automated three digit discount is provided for mailings of ten pieces or more sorted by the first three digits of the addressees' zip codes; and a fourth level of discount is provided for mailings of ten pieces or more sorted by state (i.e., the first zip code digit). The books in the jobs are typically pre-sorted to obtain an optimum level of discount within this discount structure. In the past, when errored books occurred with "multiple books per job" demand printers, reordering after completion of the job required manual re-sorting to avoid loss of postal discounts for the errored book(s) or, in a worst-case scenario, loss of discounts for the group(s) of books with which the errored book(s) are associated. Both manual reordering of errored books and manual re-sorting of reprinted books introduced delay and costs into the printing process.
As mentioned briefly above, demand printers are often provided with various downstream auxiliary finishing devices such as folding devices, trimming devices, weighing devices, binding devices, gluing devices, dot wackers, tip-ons, card feeders, strappers, and/or mechanical co-mailers. Such auxiliary devices can be coupled to the press thereby permitting processing of books as they are printed, or they can be free-standing thereby requiring transportation of books from the press to the auxiliary device for further processing. As with the demand printers discussed above, such auxiliary devices can foul a printed book from time to time. In the past, when the press operator noted that an auxiliary device had outputted an errored book, the operator would typically be required to manually reorder the errored book and subsequently re-sort the reprinted and finished book if postal discounts were desired thereby introducing further delay and costs into the printing process.